新的聚合物支载硼氢负离子还原剂系统研究 3: 聚合物支载还原剂III

硼氢化钠的低分子还原系统研究很多,但其聚合物支载还原剂相对来说就很少,而且仅以强碱型阴离子交换树脂来制备的聚合物试剂。为了寻找用途更广泛的、新的聚合物支载还原剂,我们进行了硼氢负离子的聚合物还原系统的研究;发现能用弱酸型阳离子交换树脂制备出新的聚合物支载还原剂。前文报道了用NaBH_4的水溶液和阴离子交换树脂     

离子交换-双氧水氧化法制备纳米CeO2晶体

以99.995% Ce(NO₃)₃和强碱性阴离子交换树脂为原料，采用离子交换-双氧水氧化法合成制备出纳米CeO₂晶体。并就离子交换反应中的Ce³⁺浓度、树脂加入速度和离子交换温度及H₂O₂加入速度等条件对CeO₂粒径的影响进行了探讨，得出了离子交换-双氧水氧化法制备纳米CeO₂晶体的最佳工艺条件。FTIR、TEM分析表明，离子交换法无需对合成的Ce(OH)₃溶胶进行洗涤即可去除NO₃^-、CO₃^2-等阴离子杂质，并用H₂O₂将该溶胶氧化，经真空干燥可制得粒径分布均匀，平均晶粒尺寸约3 nm，高纯度的CeO₂粉体。     

聚合物复合材料填充剂的表面性质及其分散性的研究

本文通过反气相色谱技术研究了未处理的、硅烷偶联剂处理的和钛酸酯偶联剂处理的三种Al(OH)_3粉末的表面性质,并通过塑化仪和扫描电子显微镜研究了Al(OH)_3填充聚丙烯体系的流变行为及其在聚丙烯中的分散效果.结果表明Al(OH)_3的表面性质对其在聚丙烯介质中的分散效果有着重要的影响.     

TiO2-SiO2光催化纸业废水有色有机物的降解

研究了TiO2-SiO2混合氧化物对纸业废水中有色有机物的吸附与光催化降解效率．常温下．TiO2对纸业废水中有色有机物的吸附符合Freundlich模型，Qe=0．239Ce^0.791。TiO2-SiO2混合氧化物对纸业废水中有色有机物的吸附与光催化降解效率与催化剂样品的组成有关，光催化降解效率也与TiO2-SiO2表面总酸量有关．     

Adsorption of organics on activated carbon cloth at zero surface coverage

Summary Adsorption properties of activated carbon cloth were investigated by gas-solid chromatography. Retention of several organic compounds was measured in the temperature range from 200 to 250°C. The gas/solid distribution coefficients and the related thermodynamic function of adsorption at zero surface coverage were determined. The obtained experimental data were used to explain the adsorbent-adsorbate interaction.     

Effect of the ionic strength of salts on retention and overloading behavior of ionizable compounds in reversed-phase liquid chromatography I. XTerra-C18

The influence of the salt concentration (potassium chloride) on the retention and overloading behavior of the propranolol cation (R'-NH2+ -R) on an XTerra-C18 column, in a methanol:water solution, was investigated. The adsorption isotherm data were first determined by frontal analysis (FA) for a mobile phase without salt (25% methanol, v/v). It was shown that the adsorption energy distribution calculated from these raw adsorption data is bimodal and that the isotherm model that best accounts for these data is the bi-Moreau model. Assuming that the addition of a salt into the mobile phase changes the numerical values of the parameters of the isotherm model, not its mathematical form, we used the inverse method (IM) of chromatography to determine the isotherm with seven salt concentrations in the mobile phase (40% methanol, v/v; 0, 0.002, 0.005, 0.01, 0.05, 0.1 and 0.2 M). The saturation capacities of the model increase, q(s,1) by a factor two and q(s,2) by a factor four, with increasing salt concentration in the range studied while the adsorption constant b1 increases four times and b2 decreases four times. Adsorbate-adsorbate interactions vanish in the presence of salt, consistent with results obtained previously on a C18-Kromasil column. Finally, besides the ionic strength of the solution, the size, valence, and nature of the salt ions affect the thermodynamic as well as the mass transfer kinetics of the adsorption mechanism of propranolol on the XTerra column.     

Rice husk ash as an adsorbent for methylene blue—effect of ashing temperature

Utilization of one waste material to control pollution caused by another is of high significance in the remediation of environmental problems. Rice husk, an abundantly available agricultural waste, can be used as a low cost adsorbent for dyes and heavy metals in effluent streams. The possible utilization of rice husk ash as an adsorbent for methylene blue dye from aqueous solutions has been investigated. Ash samples from husks of two origins were prepared at different temperatures and their physical, chemical spectroscopic and morphological properties were determined. XRD, FTIR and SEM were some of the techniques adopted for the characterization. The samples were also analyzed for bulk density, pH, nitrogen adsorption properties and lime reactivity. Experiments of methylene blue adsorption on the ash samples were conducted using batch technique and a comparative study was made. Results were analyzed using linear, Langmuir and Freundlich isotherms. The values of separation factor indicate that most of the ash samples do adsorb the dye molecules, but in varying quantities. Calcination at 900^∘C reduces the adsorption capacity of the ash to a great extent. Regression analysis shows that the experimental data fits both Langmuir and Freundlich isotherms for certain concentration limits. The adsorbate species are most probably transported from the bulk of the solution into the solid phase through intra-particle diffusion process. Kinetics of adsorption was found to follow pseudo second order rate equation with R ²∼ 0.99. The highest adsorption capacity (Q ₀) achieved is found to be ∼690 mg/g, which is even higher than the values reported for activated carbon from rice husk. The adsorption capacity of the ash samples are in good agreement with their surface area and pore volume.     

In situ determination of adsorption kinetics of proteins in a finite bath

A method for fast in situ measurement of adsorption kinetics based on a finite bath was developed. We modified the conventional finite bath by replacing the external loop by a dip probe which enables in situ measurement of the concentration change in the contactor. Deposition of adsorbent particles on the reflection surface of the dip probe compromised measurements. Different membranes, a polyamide, a polypropylene and a nylon membrane were tested to protect the internal reflection surface of the dip probe from fouling with adsorbent particles. The nylon membrane provided efficient protection and high mass transfer evaluated by response time experiments. Unspecific adsorption of the model protein on the membrane could also be excluded. To corroborate the measurements of the dip probe the results were compared to a conventional finite bath and to a shallow-bed. The uptake curves for human polyclonal IgG at different concentrationes (0.1-3 g/l) on rProtein A Sepharose FF and MabSelect were used as model system. The effective diffusion coefficients were determined using a pore diffusion model. These values were in good agreement for all methods.     

有机分子与聚电解质静电吸附成膜特性研究

选取多种有机分子及聚电解质，采用静电吸附自组装法制备了聚电解质，聚电解质、聚电解质，有机分子、有机分子，有机分子的复合薄膜，讨论了这些体系的静电吸附成膜特性及其成膜机理．     

几种杂多阴离子柱撑水滑石的合成与吸附行为

柱撑水滑石类层柱状阴离子粘土是一类新型层柱材料，由于其二维孔道结构的可调变性及潜在的择形催化性能，已引起人们的重视[1-3]．迄今，人们已合成了包括无机和有机阴离子，同多和杂多阴离子（Polyoxometalates，简称POMs）以及配合物阴离子在内的多种柱撑水滑石，其中同多和